An authentication method is the specific way a system confirms a user’s identity, such as a passkey, authenticator app prompt, SMS code, or hardware token. It is one layer in the sign-in and account-recovery process, and it determines what proof a user must provide before access is granted.
This matters because attackers often target the method, not just the password. In phishing and helpdesk impersonation, a criminal may push a victim to approve a fake app prompt, enroll a new passkey, or reset a factor under the guise of support. If an unauthorized method is added, the attacker can keep coming back even after a password change. Defenders should watch for new method registrations, unusual approvals, and recovery requests, and verify sensitive changes out of band.